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Almost always missing layers / underextruding

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Posted · Almost always missing layers / underextruding

Hi Mark, long time no see! How are you doing?


Great thanks, hope all is well with you.

Had some interesting results last night on the retraction issue I'm getting. Interested to hear any comments on this.

After totally cleaning the nozzle again, I started to experiment with the feed unit on the rear since I noticed it was doing some serious chewing on removal and presumably whilst printing. The white indicator was at the very top, which as I understand is correct for the version of UM2 I have, it was one of the very early ones. I decided to move this down and ended up running a print whilst this was set to the middle, I also ran the print with no retraction.

The first few layers went really well, however as per usual in these cases when my back was turned and I went to bed, the print failed so when I checked it this morning the print head had just stopped and no filament was flowing. I then reset the tension to its original setting and started the print again but this time with retraction on. This time I noticed that the filament was feeding perfectly and I managed to get a successful print.

I then decided to kick of another print, sadly having just called in over lunch, I found the print had failed although it seems this is as a result of the bed which was no longer hot. Hopefully the bed will just be a loose connection and I can then try the print again.

So all being well I am wondering if the following may have been the cause for my under extrusion issues.

1. I used XT filament and found that despite trying a variety of heat settings I couldn't get a reliable print, plus it seems to clog more than standard PLA

2. Although I cleaned the nozzle out using the Atomic Method, I think its called - so heat to 220, insert and cool to 90, perhaps there was still some residue in the nozzle as very soon after, despite an initial perfect print with PLA, I then started to experience severe under extrusion.

3. Did this blockage somehow alter the tension on the feed unit and by increasing and decreasing the tension "un set" this?

4. Interestingly to throw a spanner in the works, the under extrusion did not occur on all types of PLA, I managed to get two good results with some year old PLA sections. This could be just luck but find it odd given that the PLA was the same colour and manufacture as some new stuff (Faberdashery)

Now off to find info on the heating bed and how to take that apart to check.

Watch this space


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    Posted · Almost always missing layers / underextruding

    I find XT harder to print than PLA. Had to fiddle with the print settings to get a decent quality. When XT is left near the nozzle (or some residue remains on the nozzle itself), it tends to form dark spots that look like they could wonderfully clog the nozzle. I can't say this for sure because I haven't printed with XT that much - it is just a guess.

    Regarding the feeder tension - maybe the spring inside the feeder got stuck and you un-stuck it when you changed its tension.


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    Posted · Almost always missing layers / underextruding

    Hi Mark, I am running as follows

    .200 at 30mm/s using 200c; if there is bridging I would change to 205c

    Then for the following I am getting good results but would probably try reducing the temps by 5c...

    .300 at 60mm/s using 220c

    .150 at 50mm/s using 210c

    .300 at 50mm/s using 215c

    I think with a lot of filaments one can be off the optimum temp. by 5c or even 10c without really seeing much difference but Arctic white seems to be a bit less forgiving.

    Please note the above temps. are not from printing on a UM so you might need to do a few tests to find the offset for your printer.


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    Posted · Almost always missing layers / underextruding


    I was having terrible under extrusion problems on my brand new Ultimaker 2


    The I add a filament filter/ioler whit a little bit of canola oil and that take all the demons out of my UM2


    I hope this help to those how are having trouble whit under extrusion.

    TIP: Whit canola oil I can actually see where the filament was getting stuck inside the feeding tube.


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